Agro pedological Assessment of the Traditional Agarwood Aquilaria malaccensis growing areas of Upper Brahmaputra Valley Zone Assam

Abstract

The present investigation was carried out in some traditional Agarwood growing newlineareas of the Upper Brahmaputra valley zone of Assam for pedogenic characterization of newlinethe soils and to evaluate the soil fertility status and microbial properties of soils around newlinethe Agarwood trees of high and low market values. The plant nutrient content and newlinebiochemical properties of the leaf of both types of trees were also determined and their newlinerelation with soil properties was assessed. An attempt was also made to evaluate the newlineinfluence of different soil and plant properties on the quality of Agar trees of the area. To newlineaccomplish the objectives, ten locations were selected from three districts of the Zone. newlineThe highest number of locations (six) were selected in Golaghat district (Dhekial, newlineKakodunga, Naharani, Haanhpani, Podumoni, and Halowagaon) because of its largest newlinearea under Agarwood production. Out of the remaining four locations, two were selected newlinein Jorhat (Alengi and Pirakota) and the other two were taken from Sivasagar district newline(Namti and Mathurapur). A soil profile was exposed in each location to characterize and newlineclassify the soils. Besides 120 numbers of composite surface (0-25 cm) and subsurface newline(25-50 cm) soil samples were collected from near the trunk of good and poor quality agar newlinetrees of all the locations. In addition to soil samples, equal numbers of plant samples were newlinealso collected from these trees for the present study. newlineThe soils were dark yellowish-brown to brownish-yellow in colour and loam to newlineclayey in texture. The sand, silt, and clay content of the soil profiles varied from 28.1- newline54.5%, 19.6 -37.3%, and clay 22.7-42.8% respectively. Soil structure was mostly weak newlineto medium sub-angular blocky. The bulk and particle density of the soils ranged from newline1.19 -1.59 Mg m-3 and 2.48-2.61 Mg m-3 respectively. The average water holding capacity newlineof the soils was found to be greater than 30%. The soils were very strongly acidic to newlineslightly acidic with a pH range from 4.79 to 6.60 and found to increase with the depth of newline...